The air intake device for the internal combustion engine as described above includes the intake air path and the exhaust gas path in order to mix, for combustion in a combustion chamber, exhaust gas, blowby gas, or evaporated gas (evaporated gas of fuel) that is produced as wasted gas by driving the internal combustion engine, with combustion air.
Patent Document 1 listed below discloses a conventional air intake device for an internal combustion engine including a first exhaust gas path for supplying exhaust gas as waste gas from an EGR surge tank acting as the exhaust gas distribution header to the combustion chamber, a second exhaust gas path for supplying blowby gas as the waste gas from the interior of a cylinder head cover acting as the exhaust gas distribution header to the combustion chamber, and a third exhaust gas path for supplying evaporated gas as the waste gas from an unillustrated exhaust gas distribution header to the combustion chamber.
A downstream exhaust gas path section in each of the first to third exhaust gas paths and a downstream intake air path section of the intake air path constitute a common path.
An upstream exhaust gas path section of each of the first to third exhaust gas paths positioned upstream of the common path is provided desirably depending on a position of the EGR surge tank or the cylinder head cover.
In other words, no consideration is given to the relationship between the length of the exhaust gas path extending along the centerline of each of the exhaust gas paths and the length of the intake air path extending along the centerline of the intake air path. The length of each of the exhaust gas paths is set to a desirable value depending on the position of the EGR surge tank or the cylinder head cover.